I've used this set of servers for years, they're the fastest I know of, period. I'll back that up with some data:

              DNS Server | Comcast in Seattle  | The Planet Colo in Dallas
  Level3         4.2.2.X | 11ms ± 1.5ms  5hops | 1ms ± 0.2ms
  OpenDNS 208.67.222.222 | 35ms - 150ms 11hops | 24.9ms ± 0.1ms
  Comcast   68.87.68.162 | 90ms - 250ms 12hops | 23.4ms ± 0.1ms

Hilariously, neither OpenDNS nor Comcast are so variable in ther sluggishness when accessed directly -- The Planet is peered directly with Level3, NTT (OpenDNS's host), and Comcast. On top of that, Comcast is marginally faster than OpenDNS outside their own shitty network! The relative slowness has nothing to do with the servers themselves.